Lucas Rita Amplifiers

Found some info here.

Unfortunately the pictures in the earlier message 626041 do not show on my computer.  

The Rita on my Mk3 is 48022B.

These nice people sell new boards to replace the electronics in your old Rita.
https://www.rexs-speedshop.com/product-category/classic-british-motorcycle-electrical/lucas-rita-2/

They don't make any distinction between bikes apart from the comment about how the coils are wired on triples.

Having inherited the RITA  empire inadvertently  ( I bought all the parts) and already repairing the amplifiers I am sure that the vast majority of the amplifiers (AB11) are identical. There was a few amplifiers with different colour side panels that had a reduced advance curve for racing.(installed by Mistral) but the 48022B would be a Lucas number not a Mistral modification. I have handled several hundred but not come across the 48022B model. ALL RITA had 5 wires- 2 pickup, power +- and a coil switch lead.    aoservices.co.uk

Hey Al, that's useful to know.

How are you fixed for spare reluctors & pick-ups? You know, the bits that get wiped off when you drop it.

Are you happy for your RITA services to be publicised?

I have various installation instructions and Mistral service sheets - would you like scans?

Here's a picture of the AB11 - 48022B  box on my road bike. Came in original Lucas retail packaging as I recall.

And one of the colourful AB5s modified by Mistral. Black case = advance curve modified for 4S cam. Yellow panel = bistable amplifier for total loss battery applications.

Back in the days of the close of Mistral empire I met with John in anticipation of manufacturing an updated RITA with possible future offering of a tuneable digital box. I flew to England to meet with him and had previously bought out the US distributor . http://www.eurospares.com/elec.htm

My main interest was for commando but due to technical limitations of the RITA, I though better than to take on a new career in light of many new ignition offerings. pazon-trispark and others. I still highly recommend a RITA for MKIII for reasons stated in my article. 

http://atlanticgreen.com/boyerevolved.htm

I still have around 60+ used and many NOS units for brit-jap-italian and german bikes. (this is not an advert to sell)  

I have also repaired many AB11 boxes but certainly less these recent years. Not a lot of repairs since they rarely fail. All my nortons have RITA still mounted unless magneto powered.

I am however curious of the REX offering as I am 35 years in high power electronics and am skeptical of surface mount electronics in high power applications. Can they work ....yes. Can they tolerate the heat is my concern. I currently would prefer a reconditioned AB11 circuit board over SMD.

cheers Dave

http://atlanticgreen.com/

Some nice comments there Dave. Re REXs Speed shop board offering for the RITA, when he introduced this I was in touch with REX, but they decided to go it alone so even though I have all the RITA parts. REX 'paddels his own canoe'.

Stan thanks for offer yes of course I am in the market for RITA repairs. Your AB5 is disappointing though, the AB5 draws twice as much current that the AB11 (due to early transistor technology)

The AB11 will do the indenticle job at half the power. The reduced advance curve can easily be reproduced on an AB11 if you want. Thanks for offer for I have all the Mistral documentation. And I have lot's of reluctors and covers, in fact covers are a BOGOF (Buy one get one free)

Al, I've sent a pm about reluctors and pickups. Not the covers though which are the reason I need new pickups - unlike the Norton points cover, the RITA cover is all too easily wiped off and I've made stronger covers.

My AB5 units have been reliable and serve me well. As long as they go 2 hours on a battery charge I'm happy and so far, fingers crossed and all that, I've never noticed any fall-off in sparks.

I'm asked about RITA spares & repairs from time to time so I'll pass your details on now I know.

I cannot identify 47240A. But two yellow painted dots signifies a Bistable Amplifier- in non technical terms this means lower than 'normal' AB11 power consumption. Normal AB11 power consumption is virtually the same as traditional points/coil ignition. Bistable nominally reduces that to about 1/2. The AB5 uses 2X the power.

The Bistable was developed for use on Dynamo bikes with  low power available from the battery/generator. Ie Velocettes, Vincents. But happily usable on any Norton. Very easy to change to Std (Monostable)

48022B although quoted as a Norton Commando number does not appear to have any speciality for the Commando, directly replaceable with 47270A and 47270B. ALL RITA amplifiers have 5 wires coming out of the box. Black-Negative. White/Yellow-Positive. White/Black-coil switch. With originally a 3 pin Lucas/Rist plug, and a separate lead and 2 pin for the pickup White/Orange, White/Purple. The case of the amplifier has another Black wire that is connected to the vehicle Earth. The advance curve is dictated by the 'shape' of the reluctor, but the total height of the advance curve can be reduced from inside the amplifier (Different coloured panels on the box). For racing.

48022  uses the lucas 54982301B printed circuit board.

47270A,  47270B,both use the 54982301E. The B configuration was to use, more modern component, the goal being improved "electrical" ruggidness.

Both B and E  boards contain visually identical traces.

I have noted that inspecting two E board units, a few holes are full and on another board have no component soldered in.

On two E board units they have a jumper that is not on all units. I will need to identify the differences that these seemingly minor differences have on wave shape, amplitude, and duty cycle and the resulting change, if any, to the advance curve.

ADDED:

I have 2 yellow dot AB11 (A) and one green stripe AB11 (B) and will look into them to see if modified and characterize them if necessary.also.

Recent discussion with a REX user shows notable electrical characteristics that could be considered detrimental. This is not necessarily "my job" to do a technical review of the REX product.

However I may investigate one, but I no longer buy products just for curiosity, which I used to do over 15  years ago... like the Boyer spark jitter on voltage depression on MK3 e-start commando.  How many people know it was my article that gave that tidbit to the world?

How does that make me a bad guy?

Hi,

i have a AB11- 47270A on a commando 850 is this different to the AB11-48022B?

cheers

Mick Young

As DC says the B version does have a minor electronic alteration to make the unit more reliable BUT I do not see enough difference to worry about any use on the bike. 

The "A" had a varistor for spike protection of the output transistor. The "A" required a ground wire as the varistor safety ground path. It had a limited life in the number of overvoltage "hits" it could take before death. The varistor dies , then the transistor death soon follows

The "B" had a output transistor with internal protection triggering of the final transistor. THEREFORE... The "B" did not actually require a grounding wire. John told me so, and I fully understood why. It had much bigger number of over voltage "hits" before death.

All my repairs were done to the "B" standard.

The rita is still a fine instrument except the "long dwell" power consumption.

For my penny worth I'd go for the ignition switch at fault due to the explosion/"puff" that you experienced as this was the last action you took.

Prove it by rigging up another switch to bypass the original and give it a go, aide memoire.

Fully charged batteries help enormously.

Failing this its a case of checking through the ignition wiring for that elusive connection that is missing.

I suspect that the "puff" was caused by the coils kicking in as the ignition switch operated acting like a trigger unit.

Hope this helps.

Hot wiring is the equivalent of another switch as you suggest. On AOServices.co.uk is a FAQ for the RITA. Would suggest you check it out. To ascertain the spark, set the pickup as you show it, ie approaching the firing position, ignition on, then 'jiggle' a small screw driver in the pickup gap, this should trigger a spark. Once you have a spark the rest is down to you.

This has turned out to be a failed RITA amplifier. Now repaired and being fitted. We await next the next saga.